The interactions that take place between mammalian sensory nerves and oral epithelium will be studied during differentiation of lingual taste buds in fetal sheep. This examination of fetal nerve-epithelial interactions will provide a basis for understanding neurotrophic influences during oral-facial development. The inductive influence of non-taste nerves on lingual epithelium will be studied, as will the influence of taste nerves on non-lingual epithelium. Using Sterile surgical procedure in fetal sheep of various ages, cross-grafts of cheek epithelium to anterior tongue, and anterior tongue epithelium to cheek, will be made. Grafts will be examined histologically when lambs are born at term in the laboratory. The presence or absence of taste buds and papillae and the density of nerves in all grafts will be observed. To determine whether taste buds that may form in grafted epithelial tissues are functional, electrophysiological recordings will be made from the innervation of grafted tissues. Grafts will be stimulated with chemicals and tactile stimuli. The experiments will increase knowledge of: inductive influences in the oral cavity during development; tissue healing and epithelial grafting; underlying pathology of familial dysautonomia; taste receptor formation. This knowledge will contribute to understanding normal and abnormal craniofacial development.